Drier



1952 w. L'. KAUFFMAN, 11 2,583,850

DRIER Filed Jan. :3, 1948 5 Sheets-Sheet 1i 3nventor g (Ittorneg J 19-52 w. L. KAUFFMAN, 11 2,533,850

DRIER Filed Jan. 29, 1948 3 Sheets-Sheet 2 lhwentor I 8,; ma; k H" Jan. 29, 1952 w. L. KAUFFMAN, 11 2,533,350

DRIER Filed Jan. 29, 1948 5 Sheets-Sheet If Bnnentor Z Gimme Patented Jan. 29, 1952 DRIER Walter L. Kaufiman, II, Erie, Pa., assignor to Lovell Manufacturing Company, Erie, Pa., a corporation of Pennsylvania Application January 29, 1948, Serial No. 4,985

Tumbler type clothes driers have been made 5 Claims. (c1. 3482) with an automatic control cycle responsive to i the exhaust air temperature. Among the problems encountered have been the unwanted accumulation of lint and the high temperature of the clothes at the end of the drying cycle. This invention is intended to solve these problems through a lint trap at the point of discharge from r the drum and by a controlled over-run at the end of the drying cycle giving the dried clothes are control diagrams; Fig. 11 is a front elevation of the temperature control; Figs. 12 and 13 are edge views partly in section showing the contacts respectively in the closed and open positions; Fig. 14 is a detail of the temperature adjustment for the control; and Fig. 15 is a detail of the snap spring for the control contacts.

Referring to the drawings, I indicates a cabinet having on its front wall a door 2 for loading and unloading clothes and a control 3 provided with a start push button 4 and a temperature adjustment knob 5. The cabinet is carried on a base 6 (Fig. 3) having at its back a standard I carrying a bearing 8 for a horizontal perforate drum 9. The periphery of the drum is almost completely enclosed by a suitably supported wrap-around sheet I 0. At an upper corner of the cabinet the wrap-around sheet has an opening II for a radiant heating element I2 within a reflector I3 which focuses the heat throu h the opening I I. During the operation of the drier, air is drawn into the cabinet through suitable louvers (not shown), flows around the outer surface of the wrap-around sheet I0 and reflector I3, enters the drum t rough a slot I4 at the leading edge of t e reflector, and flows dia onally across the drum to outlet openings 5 in the wrap-around sheet. The parts heretofore described are or may be of common construction. The openin s I5 have flan es I6 proiecting through and crimped over openings H in a fan inlet duct I8, the back end of which is telescoped over t e inlet IQ of a fan casing I911, and the front end of hich telescopes over an inwardly extending flange around an opening sance.

2 I 2I on the front wall of the cabinet. The opening 2| is normally closed by a cover 22 carrying a cylindrical filter screen 23 within the inlet duct l8. The filter screen has an indented trough 24 opposite the openings IS. The inner end of the screen 23 telescopes within the fan inlet I 9. As best shown in Fig. 8, the part of the fan inlet l9 opposite the trough 24 is blocked by a wall 25 having peripheral flanges 26 underlying and helping support the side walls 24a, 24b of the trough.

The air stream flowing through the openings I5 carries a small amount of entrained lint, the accumulation of which in time becomes a nui- Being moist, due to the high humidity of the discharged air, the lint is sticky and tends to dry in an adherent coating.

There is no lint problem in the casing surrounding the drum 9. Apparently the air currents set up by the rotation of the drum sweep the adjacent casing surfaces clear. The entrained lint in the air discharged through the openings I5 is caught in the trough 24, tending to pile up on the wall 24b opposite the trailing lips I5b of the openings I5. This is due to the tangential component of motion of the air in the direction of the drum rotation. When the trough is full, the air flows through a by-pass or overflow passage to one side of the normal path of flow. In Fig. 5, a by-pass passage 21 is shown at the front of the filter screen. In Fig. 6, by-pass passages 21a and 27b are shown so as to be beneath the leading lips I5a of the openings I5 when the screen is assembled in the drier.

The accumulated lint may be removed by pulling handle 28 on the cover 22 removing the screen 23 from the duct I 8. Any lint which falls off the screen can be easily removed from the smooth inner surface of the duct I8. The lint is in a felted condition which makes it easy to handle.

In the fan casing Hat is an impeller 29 having a hub 30 adjacent the back wall 3| of the fan casing. The rear surface of the hub carries a spiral rib 32 which keeps lint clear of the space between the hub and wall 3|. Anv lint accumulatin on the wall 3! is scraped off and moved outward by the spiral rib. This is important if per odic cleaning of the lint trap is neglected.

The fan casin has a discharge 33 over which is telescoped a discharge duct 34 having its front end discharging into the toe space 35 at the front of the drier.

Extendin through the back wall 3| into the discharge 33 is a thermostat bulb 36 for autopletelyr dry/ clothesrespond" to-ipartia'lly dry clothes.

:part'of the-casing around the drum.

cuit to the heating element |2 through a temperature limiting thermostat 39. Contacts 3? also close a circuit to a motor 45 driving the fan and drum. The contacts 3? are bridged by a normally open thermostat ll. responsive to casing temperature and in series with contacts 42 controlled by a cam 43 turned by the temperature adjustment knob The knob controls amadjustment. indicated. at 44- (through a mechanicalconnection indicated by dotted lines in: 9' and which determines'the dryness or. therclothes at the end of the drying cycle. Thehighest-temperature corresponds to com- Lower temperatures cor- The lowest temperature. shuts the drier down prevents any drying. Thus the operator by adjusting the knob. 5 preselects the dryness of the clothes. The thermostats 39 and 4| may be located on the top of the wrap around sheet ill to the right of: the reflector l3'as shown in. Figs; 2 and 3. In these locations the thermostats respond to the hottest The adjustment 4-4,.described in detail later, determines the point at which the" bellows 55, associated with theithermostat'bulb. 35, opens the contacts 3'1! and. 33. In. the; lowest temperature position the adjustmentis such that the contacts 3'! and 38' are open atroom temperature.

The thermostat 4| closes'as soon as the drier casing isup tor'a temperature somewhat below the: normal operating temperature. The closing ofithe thermostat 4| completes anv auxiliary circuit' around: the-motor contacts 3? which keeps the motor running after the opening of the contacts37 and. 3:8 by the bellows 45. This overrumperiod'lastsuntil the casing has cooled toa point at which: the clothes are comfortable to handle. .Thet'th'ermostat. 4|, in effect, adds an automatic cool. oiT' period to the end of the aut0- matic drying cycle, controlled by the thermostat bulb 3.5.

.It occasionally happens that the operator wishes to open the door 2 during the drying cycle reasoned pieces left out of the load. If. these pieces are added. before the thermostat ii has closed-,i't is'o-nlynecessary for theoperator to pull out on' the start button 4- which stops the motor and the power input to the heating element It. However, if-the casing has warmed up to a point at which the thermostat 4-3 has closed, the motor will keep on: running if the drier is stopped by pulling out on the start button. This introduces confusion since the drier does not always behave in the same manner. In the present control this confusion is eliminated by the cam 43 on the shaft carrying the temperature adjustment knob 5. To

stop. thedrier to add additional pieces the opera tor turns the temperature adjustment knob to the lowest position, which may be marked CE. In this position the cam 43 opens the contact 42 and. breaks the auxiliary circuit controlled by thetemperature over-run. thermostat 4|. With this control there is no possibility of confusion. The operator always starts the automatic drying cycle by pushing the start button 4. Whenever the operator turns the temperature adjustment knob to the off position, the drier stops. Because the ofi position corresponds to the lowest temperature adjustment the contacts 31 and 38 are also open. The control diagram, shown in Fig..l0.,.has correspondingly numbered parts and operates in the same manner except that the temperature overrun thermostat 4| is connected in series with the motor and the contacts 42. Upon pushing the start button the motor circuit remains open until. the drier casing comes up to the desired temperature. At this point the temperature overrun thermostat closes the motor circuit and keeps the motor circuit closed after the contacts 3! and 3.8 have been opened by the thermostat bulb 45. When the operator wishes to interrupt the automatic drying cycle. to add additional pieces, the knob 5 is turned to the off position, opening the contacts 42 and interrupting the motor. circuit and also the circuit to the heating element. The control diagrams of Figs. 9 and 10-, except for the addition of the cam 43 and the contacts.

42, are as shown in my application Serial No. 652,362, filed March6, 1946, now Patent 2,548,313.

The control 3 for the drier is. shown. in. detail in Figs. 11-15, inclusive. slidably guided in a bracket 45 and has its inner end connected to the free end of a bowed, nearly rigid strip 4? pivoted at 48 on a tab 49 Adjacent the pivot 48 the. strip 4? has projections5l1 which bear on a flange 5| on a shaft 52. The resilience of the strip 4'? is such thatthroughout the nor;-

mal operating range the projections. 58- aremain tained in contact with the flange 5| by the. inherent resiliency of the strip 4'1. The; freesend of the strip 41 carries a stop 53 which in the closed position is pressed. againsta surface. 54 by an arched spring 55 which, as: shownin Fig.

15, is the central member of an E-shaped spring I steel stamping. The side legs 56' of the. stamping. are anchored at 51 on the control casing... .In the position shown in Fig. 12 the spring 55 exerts a light pressure in the direction to hold the stop 53-against the surface 54. The base of the=-.E- shaped stamping has fixed thereto an; arm. 58 pivotally carrying a holder 50 for the contacts 3] and 38. The spring 55 in the closed position exerts a pressureonthe holder 5|! in a direction to maintain the contacts ill-and 33"closed.. It will be understood that the strip 4. '|-has-sui-table clearance opening for the shaft 52 and forthe contact carrying arm 59. 1

The contacts 31 and 38 maybe opened by pul1- ing out on the start button 4.. This forciblymoves the free end of the strip.4.'| downward with, refs erence to the arched spring 55. This changes the line of action-of the spring, resulting,- inxa snap action movement to the position-shown in Fig. 13. In this position the free end of. the

. strip 41 rests against a stop 5|, and thespring .Upon expansion of the bellows 45., due -to-an.in-- crease in temperature of the thermostat bulb 36,

the bellows force the shaft 52-. downward, thereby moving the flange 5| and lowering thepivot point. of the projection 5 3 on-the. .fiange 5|. This The start button 4is by turning the temperature adjustment knob 5- to the lowest temperature position. Rotation of.

the knob causes the reduced portion 63 of the; shaft 52 to be threaded in and out of the parts 62, thereby changing the relative position of the flange 5|. This adjusting movement is permittedby a pin and slot connection 64. Turning the temperature adjustment to the lowest position also results in a downward movement of the flange 5|, lowering the pivot point for the strip 47 to a point at which the contacts 31 and 36 are open.

The temperature adjustment knob shaft carries the cam 43 previously described in connection 1 with the control diagram. of Figs. 9 and 10. In. the normal position the cam 43 is spaced from a spring arm 65 carrying one of the contacts 42.

In the lowest or off position of the temperature adjustment knob the cam 43 engages the arm 65 and separates the contacts 42 as indicated in Fig. 13. I claim:

1. In a clothes drier of the type having a casing containing a drum for tumbling the clothes and having an air inlet to the casing, and means withdrawing air from the casing, the combination of a duct for the air having an inlet opening in a side wall communicating with the casing, a

hollow screen insertable in the duct having a lint collecting recess in its outer surface opposite the inlet opening and having its interior communicating with the air withdrawal means.

2. In a clothes drier of the type having a casing; containing a drum for tumbling the clothes and having an air inlet thereto, the combination of into the fan intake, a lint collecting trough in the screen opposite said inlet opening, and means blocking the end of the trough at the fan in take. l

3. In a clothes drier, a drum for tumbling clothes, a casing enclosing the periphery of the drum and having an air inlet thereto, a duct havf ing a side wall adjacent the outer wall of the casing, said duct having an inlet opening through v the adjacent casing and duct walls, a fan having its its intake connected to one end of the duct, a hollow filter screen insertable through the opposite end of the duct and having its interior leading to the intake, and a lint collecting recess in the screen opposite the inlet opening.

4. In a clothes drier of the type having a casing containing a drum for tumbling the clothes and having an air inlet thereto, and means withdrawing air from the casing, the combination of a duct for the air having an inlet opening in a side wall communicating with the casing, a screen in the duct having a lint collecting recess intercepting the air flowing through the inlet opening, and an open overflow passageway around the screen to one side of the normal path of air flow through the inlet opening.

5. In a clothes drier of the type having a retatable drum for tumbling clothes, a casing enclosing the periphery of the drum and having an air inlet thereto, an axially extending duct having a side wall adjacent the outer wall of the casing, said duct having an elongated axially extending inlet opening through the adjacent casing and duct walls, a hollow filter screen having a trough intercepting the air flowing through the inlet opening, air exhaust means communicating with the interior of the screen and discharging to the outside air, and an open overflow passageway through the screen to the interior thereof under the leading edge of the inlet opening as regards the direction of rotation of the drum.

WALTER L. KAUFFMAN, 11.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,193,305 Slagle Aug. 1, 1916 1,339,260 Hurxthal May 4, 1920 1,675,160 Carroll June 26, 1928 1,756,821 Groen Apr. 29, 1930 1,966,405 Galson et a1. July 10, 1934 1,996,253 Otis Apr. 2, 1935 2,027,590 Hirsch Jan. 14, 1936 2,050,625 Orr Aug. 11, 1936 2,314,748 White Mar. 23, 1943 2,315,354 Shanman Mar. 30, 1943 2,334,025 ONeill Nov. 9, 1943 2,390,504 Berger Dec. 11, 1945 2,398,880 Broglie Apr. 23, 1946 2,403,416 Vandegrifi July 2, 1946 2,406,494 Ferris Aug. 27, 1946 2,505,041 Gorsuch Apr. 25, 1950 

